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	2022-07-20: What If We Live in a Superdeterministic Universe? 11:54: And that’s … impossible because if you trace the past lightcone of any two points in the observable universe back far enough they will overlap.
	2022-06-15: Can Wormholes Solve The Black Hole Information Paradox? 02:24: ... amount of information   hidden by a system - information not observable in the system’s gross properties. Black holes   have huge entropy ...
	2022-04-20: Does the Universe Create Itself? 16:10: ... the cosmic event horizon would have wavelength roughly the size of the observable universe. Unfortunately that makes it not very detectable without a ... 17:39: ... fact - if you calculate the size of a black hole with the mass of our observable universe - adding together all the stars, dark matter, other black ... 16:10: ... the cosmic event horizon would have wavelength roughly the size of the observable universe. Unfortunately that makes it not very detectable without a universe-sized ... 17:39: ... fact - if you calculate the size of a black hole with the mass of our observable universe - adding together all the stars, dark matter, other black holes, ...
	2022-03-23: Where Is The Center of The Universe? 12:47: ... and that if you zoom out to many, many, many times larger than the observable universe, everything evens out ...
	2022-02-23: Are Cosmic Strings Cracks in the Universe? 08:50: ... expanding universe stretched them up to the size   of the observable universe. We actually expect  multiple nucleation events in each ...
	2022-01-12: How To Simulate The Universe With DFT 00:00: ... you used every particle in the observable universe to solve the schrodinger equation and do full quantum ... 11:50: From there you can go ahead and calculate whatever observable you’re interested in. 00:00: ... you used every particle in the observable universe to solve the schrodinger equation and do full quantum simulation of some ... 10:29: ... say that you can map from this charge density to the interesting observables - like the energy of the system, without having to go through the ... 12:22: ... - the density distribution - could be mapped to all sorts of useful observables. ... 10:29: ... say that you can map from this charge density to the interesting observables - like the energy of the system, without having to go through the ...
	2021-12-29: How to Find ALIEN Dyson Spheres 12:08: There are hundreds of billions of galaxies in the observable universe.
	2021-11-17: Are Black Holes Actually Fuzzballs? 01:14: ... no information from the matter that fell into a black hole should be observable on the surface - the so-called no-hair theorem, which says that the only ... 01:58: ... phrasing that black holes “have no hairs” to describe the absence of observable microstates in a black hole, which, on the surface, seems to contradict ... 02:56: The no-hair theorem says that there’s no information beyond charge, mass and spin that’s observable above the event horizon. 01:58: ... phrasing that black holes “have no hairs” to describe the absence of observable microstates in a black hole, which, on the surface, seems to contradict his black ...
	2021-10-05: Why Magnetic Monopoles SHOULD Exist 07:34: ... different sides of the string is exactly one wave cycle - which means no observable ... 12:16: ... things far apart that there may be very few remaining in our entire observable ... 07:34: ... different sides of the string is exactly one wave cycle - which means no observable difference. ... 12:16: ... things far apart that there may be very few remaining in our entire observable universe. ...
	2021-09-21: How Electron Spin Makes Matter Possible 02:18: ... fact that all electrons, for example, are exactly the same - there is no observable change when you swap two electrons. Combining spin behavior and ... 08:00: ... We’ll call it Psi. Psi gives the distribution of probabilities of some observable - for example, the location of the electron around the atom. Psi is ... 09:45: ... Doesn’t that give us a way to “distinguish” the swap? Actually no - no observable property is changed by the swap. Remember, that we only “observe” the ... 08:00: ... We’ll call it Psi. Psi gives the distribution of probabilities of some observable - for example, the location of the electron around the atom. Psi is really ... 02:18: ... fact that all electrons, for example, are exactly the same - there is no observable change when you swap two electrons. Combining spin behavior and ... 09:45: ... Doesn’t that give us a way to “distinguish” the swap? Actually no - no observable property is changed by the swap. Remember, that we only “observe” the square of ...
	2021-08-18: How Vacuum Decay Would Destroy The Universe 10:10: ... for a single such bubble to be likely to appear somewhere in our observable universe.   So, somewhere between vaguely  unlikely and ...
	2021-08-10: How to Communicate Across the Quantum Multiverse 07:14: ... from linearity in the Schrodinger equation would add extra non-linear observables to the wavefunction. The normal linear observables are things like ... 07:50: ... In a single 1991 paper, Polchinski showed how Weinberg’s “non-linear observables” would make it possible to achieve some pretty crazy science fiction ...
	2021-06-23: How Quantum Entanglement Creates Entropy 12:35: ... becomes increasingly inaccessible,   leaving only crude observable properties - for example, thermodynamic properties   like ...
	2021-06-16: Can Space Be Infinitely Divided? 06:02: ... we start to notice something. The photon is starting to produce an observable   gravitational field. Even though photons are massless, if enclosed ...
	2020-11-04: Electroweak Theory and the Origin of the Fundamental Forces 04:50: ... determines the probabilities of certain outcomes being measured for observables like particle position and ... 05:18: ... however you like at any point in space and still get the same physical observables. ...
	2020-10-13: Do the Past and Future Exist? 06:58: Our entire time-slice of our present is never observable in the present. 09:04: ... the effect is tiny, but the “present” at the edge of the observable universe veers back and forth by a couple of centuries every time you ...
	2020-07-28: What is a Theory of Everything: Livestream 00:00: ... to give a plug to my friend eric weinstein he has this idea of the observable verse in his theory i saw i think we should have a marketplace of ...
	2020-05-11: How Luminiferous Aether Led to Relativity 09:02: ... quite a bit smaller than a single wavelength of light would produce observable shifts in the fringe pattern. And this is exactly the method that LIGO ...
	2020-03-31: What’s On The Other Side Of A Black Hole? 13:01: ... instead causes quantum states to become correlated with macroscopic observables. The entanglement is dispersed through the environment, but in a coherent ...
	2020-03-16: How Do Quantum States Manifest In The Classical World? 03:37: ... of other states. So again - why are only certain quantum states observable on large scales? The answer lies in ... 13:22: ... the measurement problem it only tells us why certain quantum states are observable on macroscopic scales while Schroedinger Cat states - weird ... 13:47: ... the framework of decoherence and these propagating pointer states. The observable qualities of reality - object positions, feline mortality statuses, even ...
	2020-03-03: Does Quantum Immortality Save Schrödinger's Cat? 00:39: ... existing in many states at the same time, to having only one clear observable state at the moment of ...
	2020-02-11: Are Axions Dark Matter? 12:47: ... 13.5 billion years it would be around 10^10^50 times the size of our observable universe. And that sounds about right. He then compares that to an ... 15:20: ... that is itself large enough to fit all possible configurations of observable universe sized regions. The volume would want to be 10^10^123 (or 90) ... 12:47: ... 13.5 billion years it would be around 10^10^50 times the size of our observable universe. And that sounds about right. He then compares that to an estimate of the ... 15:20: ... that is itself large enough to fit all possible configurations of observable universe sized regions. The volume would want to be 10^10^123 (or 90) times our ...
	2020-02-03: Are there Infinite Versions of You? 09:40: For our 46-billion light year observable universe there are definitely no more than 2^10^123 possible unique configurations. 09:52: As long as the greater universe has more than than that many observable universe-sized regions, one of them should be identical to this one. 10:31: ... this may never be testable - we can measure the observable part of the universe to greater and greater precision and see if it has ... 09:40: For our 46-billion light year observable universe there are definitely no more than 2^10^123 possible unique configurations. 09:52: As long as the greater universe has more than than that many observable universe-sized regions, one of them should be identical to this one.
	2020-01-27: Hacking the Nature of Reality 00:43: ... mathematical description should depend only on observable quantities - in this case, the mysterious frequencies of light produced ... 01:30: ... Neils Bohr passionately advocated it, insisting that matters are the observables - the measurable start and end points of an ... 04:10: ... field theory of the internal nucleus, but rather by understanding the observables ... 04:25: In this case the observables were the particles that entered and left the nucleus in a scattering experiment. 12:56: ... takes Heisenberg’s old philosophy to the extreme - “only consider the observables”- the amplituhedron doesn’t just eliminate the fiddly mechanics of quantum ... 01:30: ... Neils Bohr passionately advocated it, insisting that matters are the observables - the measurable start and end points of an ...
	2019-11-18: Can You Observe a Typical Universe? 00:45: ... Way is an ordinary galaxy among 100s of billions of galaxies in the observable ... 05:45: All particles in the observable universe were packed together in a subatomic-sized dot. 08:33: For example a fluctuation the size of a galaxy is insanely more likely than one the size of our observable universe. 00:45: ... Way is an ordinary galaxy among 100s of billions of galaxies in the observable universe. ... 05:45: All particles in the observable universe were packed together in a subatomic-sized dot. 08:33: For example a fluctuation the size of a galaxy is insanely more likely than one the size of our observable universe.
	2019-10-15: Loop Quantum Gravity Explained 03:33: ... time, momentum, energy - mathematical expressions that represent the observable properties of the object or system that you’re trying to ...
	2019-10-07: Black Hole Harmonics 02:14: ... – which intensify as the black holes approach merger, only becoming observable in the last fraction of a ...
	2019-09-30: How Many Universes Are There? 00:24: ... it: the observable part of our universe is 93 billion light years across, and that’s just a ... 12:51: But it still should NOT be surprising that we don’t see evidence of bubble collisions in our observable universe.
	2019-08-06: What Caused the Big Bang? 00:43: ... being: why is matter and energy so smoothly spread out across the entire observable ...
	2019-07-25: Deciphering The Vast Scale of the Universe 00:30: In fact there are surely more entire worlds in the observable universe than there are grains of sand on this one.
	2019-05-16: The Cosmic Dark Ages 00:04: ... era. Somewhere between 10 and 1000 billion trillion stars fill the observable universe with light. But there was a time before the first star ...
	2019-04-03: The Edge of an Infinite Universe 00:37: For example we have the “observable universe” – that patch that we can see, and beyond which light has not yet had time to reach us. 00:57: Our observable universe is like a tiny patch of land in a vast plain. 00:37: For example we have the “observable universe” – that patch that we can see, and beyond which light has not yet had time to reach us. 00:57: Our observable universe is like a tiny patch of land in a vast plain.
	2019-02-07: Sound Waves from the Beginning of Time 13:43: Well, the answer is- it depends on what size you consider. For the entire observable universe?
	2018-11-21: 'Oumuamua Is Not Aliens 07:42: But until someone does a proper calculation to show that tumbling must change in an observable way, this is not a serious argument.
	2018-10-25: Will We Ever Find Alien Life? 16:40: ... belief or rather valuing the capacity of science to make concrete, observable predictions based on evidence-based models and that any interpretation ...
	2018-10-18: What are the Strings in String Theory? 01:10: So surely there exists a deeper set of cogs and wheels, a theory that brings all observable phenomena into the same mechanical framework.
	2018-10-10: Computing a Universe Simulation 03:34: ... that the maximum information content, the Bekenstein bound, of the observable universe is around 10 to the power of 120 bits based on its surface ... 03:59: ... bound suggests that we could hold all of the information in the observable universe within a storage device smaller than the observable universe, ... 05:13: ... informationally speaking, you could store the entire observable universe of non-radiation particles on the surface area of a black hole ... 08:04: ... the energy of the system, we use the mass of the observable universe, around 10 to the power of 52 kilograms, and then apply good ... 03:34: ... that the maximum information content, the Bekenstein bound, of the observable universe is around 10 to the power of 120 bits based on its surface ... 03:59: ... bound suggests that we could hold all of the information in the observable universe within a storage device smaller than the observable universe, which ... 05:13: ... informationally speaking, you could store the entire observable universe of non-radiation particles on the surface area of a black hole the size ... 08:04: ... the energy of the system, we use the mass of the observable universe, around 10 to the power of 52 kilograms, and then apply good old e equals ...
	2018-10-03: How to Detect Extra Dimensions 08:14: ... itself, which defines the three-dimensional structure on which our observable universe exists, can actually expand into the extra fourth spatial ... 10:49: There was no observable leakage of gravity into extra spatial dimensions, pretty much ruling this out as an explanation for dark energy. 08:14: ... itself, which defines the three-dimensional structure on which our observable universe exists, can actually expand into the extra fourth spatial ...
	2018-09-20: Quantum Gravity and the Hardest Problem in Physics 00:00: [MUSIC PLAYING] MATT O'DOWD: Between them, general relativity and quantum mechanics seem to describe all of observable reality. 14:35: dabeste points out that it's important to emphasize that you're talking about the observable universe, not the entire universe. 14:43: ... size of the storage device needed to store all of the information in the observable ... 14:53: I said "observable" near the start of the episode. 14:56: But I dropped that "observable" part a couple of times later on. 00:00: [MUSIC PLAYING] MATT O'DOWD: Between them, general relativity and quantum mechanics seem to describe all of observable reality. 14:35: dabeste points out that it's important to emphasize that you're talking about the observable universe, not the entire universe. 14:43: ... size of the storage device needed to store all of the information in the observable universe. ...
	2018-09-12: How Much Information is in the Universe? 01:07: How much information does it take to describe the entire observable universe? 05:04: ... observable universe has a surface area of 10 to the power of 120 to 10 to the power ... 06:02: The observable universe contains something like 10 to the power of 80 protons. 06:27: The cosmic microwave background has around 10 to the power of 89 photons across the observable universe. 09:47: How large a black hole computer would you need in mass and radius to contain enough data to simulate the entire observable universe? 15:24: ... reliably eliminate all of the 10 to the power of 80 protons in the observable universe, you need around 265 half-lives, or 10 to the power 42 to 43 ... 01:07: How much information does it take to describe the entire observable universe? 05:04: ... observable universe has a surface area of 10 to the power of 120 to 10 to the power of 124 ... 06:02: The observable universe contains something like 10 to the power of 80 protons. 06:27: The cosmic microwave background has around 10 to the power of 89 photons across the observable universe. 09:47: How large a black hole computer would you need in mass and radius to contain enough data to simulate the entire observable universe? 15:24: ... reliably eliminate all of the 10 to the power of 80 protons in the observable universe, you need around 265 half-lives, or 10 to the power 42 to 43 ...
	2018-08-23: How Will the Universe End? 06:45: So in something like 10 to the power of 39 or 10 to the power 40 years, all protons in the observable universe will be gone.
	2018-07-25: Reversing Entropy with Maxwell's Demon 01:31: ... physics-speak-- that could produce the same observed set of macroscopic observables, or the same ...
	2018-07-18: The Misunderstood Nature of Entropy 04:11: For a given set of large-scale observable properties, every possible configuration of particles that could give those properties is equally likely.
	2018-07-11: Quantum Invariance & The Origin of The Standard Model 02:49: The best we can do is make a measurement of physical observables, like position or momentum. 02:54: The wave function can represent different observables and it determines the distribution of possible results of measurement of those observables. 04:40: In fact, as long as you make the same shift across the entire wave function, all the observables are unchanged. 05:56: That shouldn't change our probabilities for the positions of the particles, but what about observables besides positions?
	2018-06-20: The Black Hole Information Paradox 08:11: ... that there are certain pairs of quantum-observable complimentary observables, like position and momentum, that can't both be perfectly measured at the ...
	2018-05-16: Noether's Theorem and The Symmetries of Reality 07:45: ... phase of an oscillation in a quantum field by any amount, and the observable properties of that field, like its particles, don't ...
	2018-04-11: The Physics of Life (ft. It's Okay to be Smart & PBS Eons!) 01:24: ... energy being concentrated in your cup of coffee or all the matter in the observable universe being crunched into an infinitely dense point are low ...
	2018-01-17: Horizon Radiation 01:01: ... no information can travel or the cosmological horizon that limits the observable ... 12:56: Extremely large quakes can set the entire star ringing, which is observable in its effect on the extremely regular flashes of its pulsar jet. 01:01: ... no information can travel or the cosmological horizon that limits the observable universe. ...
	2017-10-25: The Missing Mass Mystery 00:18: ... PLAYING] Our astronomical surveys have revealed an observable universe full of hundreds of billions of galaxies, each of them with as ... 00:41: When we extrapolate observations to the entire observable universe, we find a billion trillion suns worth of mass. 00:18: ... PLAYING] Our astronomical surveys have revealed an observable universe full of hundreds of billions of galaxies, each of them with as many ... 00:41: When we extrapolate observations to the entire observable universe, we find a billion trillion suns worth of mass.
	2017-09-20: The Future of Space Telescopes 11:19: The neutron star would be totally disrupted when it got very close to the black hole, producing a blast of observable radiation.
	2017-08-30: White Holes 08:34: Even though this type of white hole isn't observable, some physicists have taken the description very seriously.
	2017-08-10: The One-Electron Universe 10:59: ... we talked about the controversial evidence that many galaxies in the observable universe are drifting very slightly towards a point beyond the cosmic ... 11:23: ... assuming it's caused by a gravitational influence beyond the edge of the observable universe, then yeah, it no longer exerts a force on ... 10:59: ... we talked about the controversial evidence that many galaxies in the observable universe are drifting very slightly towards a point beyond the cosmic ... 11:23: ... assuming it's caused by a gravitational influence beyond the edge of the observable universe, then yeah, it no longer exerts a force on ...
	2017-08-02: Dark Flow 00:08: It may be that much of the matter in the cosmos is drifting due to the ancient gravitational pull of something outside the observable universe. 05:07: But what if you could measure the effect from hundreds of clusters across the observable universe? 07:50: ... the dark flow, because that flow seems to affect galaxies across the observable universe, or to two and a half billion light years at least, far beyond ... 08:08: ... of a gravitational attraction towards something beyond the edge of the observable ... 08:32: In the earliest instance of the Big Bang, the observable universe was compressed into a subatomic scale. 08:58: ... horizon, there exists a region of much more stuff, a different bubble of observable universe with more galaxies, more clusters, more dark ... 09:40: ... of a neighboring region of the greater universe, beyond the horizon of observable ... 00:08: It may be that much of the matter in the cosmos is drifting due to the ancient gravitational pull of something outside the observable universe. 05:07: But what if you could measure the effect from hundreds of clusters across the observable universe? 07:50: ... the dark flow, because that flow seems to affect galaxies across the observable universe, or to two and a half billion light years at least, far beyond the ... 08:08: ... of a gravitational attraction towards something beyond the edge of the observable universe. ... 08:32: In the earliest instance of the Big Bang, the observable universe was compressed into a subatomic scale. 08:58: ... horizon, there exists a region of much more stuff, a different bubble of observable universe with more galaxies, more clusters, more dark ...
	2017-04-05: Telescopes on the Moon 01:51: ... it can see into near ultraviolet wavelengths and in the visible range observable within our ...
	2017-01-25: Why Quasars are so Awesome 06:49: But when viewed from halfway across the observable universe, that is impossibly tiny.
	2017-01-11: The EM Drive: Fact or Fantasy? 08:05: ... he argues demonstrates that such a medium can reproduce certain quantum observables, like the energy levels of the hydrogen ...
	2016-10-12: Black Holes from the Dawn of Time 02:35: It's thought that these fluctuations originally formed when the entire observable universe was smaller than a single atom.
	2016-09-29: Life on Europa? 09:57: ... first, the simplest observable difference between the predictions of a local hidden variable theory ...
	2016-09-21: Quantum Entanglement and the Great Bohr-Einstein Debate 07:13: ... John Stewart Bell figured out a set of observable results, the so-called Bell inequalities, that we'd expect to see in the ...
	2016-06-22: Planck's Constant and The Origin of Quantum Mechanics 00:15: You might not expect the quantum behavior of the microscopic to be observable on all scales of the universe, but it is.
	2016-06-15: The Strange Universe of Gravitational Lensing 12:58: ... function gets so hopelessly mixed with those of other particles that its observable quantum behavior can't be ...
	2016-05-04: Will Starshot's Insterstellar Journey Succeed? 10:40: So dark energy only has an observable effect when its density is at least comparable to the density of regular matter.
	2016-04-27: What Does Dark Energy Really Do? 10:16: If positively curved, that would mean a finite but very, very large greater universe with a volume at least 250 times that of our observable universe. 11:12: And even then, they don't cover the entire observable universe. 10:16: If positively curved, that would mean a finite but very, very large greater universe with a volume at least 250 times that of our observable universe. 11:12: And even then, they don't cover the entire observable universe.
	2016-04-06: We Are Star Stuff 12:56: Well, we can sort of answer that for two particles at opposite sides of the currently observable part of the universe.
	2016-03-30: Pulsar Starquakes Make Fast Radio Bursts? + Challenge Winners! 04:55: That's the mass of all the protons and neutrons in the observable universe. 05:11: ... the proton, and we get that there are 6 by 10 to the 79 protons in the observable universe, and just as many ... 04:55: That's the mass of all the protons and neutrons in the observable universe. 05:11: ... the proton, and we get that there are 6 by 10 to the 79 protons in the observable universe, and just as many ...
	2016-03-23: How Cosmic Inflation Flattened the Universe 00:49: The observable universe is impossibly huge. 04:49: It goes like this-- start with a universe so crunched down that the entire currently observable part of it was all causally connected. 00:49: The observable universe is impossibly huge.
	2016-03-16: Why is the Earth Round and the Milky Way Flat? 11:42: Our observable universe was a tiny speck in that volume. 12:16: And at the moment of recombination, when the CMB was emitted, it was emitted by all of the observable universe and beyond at the same time. 11:42: Our observable universe was a tiny speck in that volume. 12:16: And at the moment of recombination, when the CMB was emitted, it was emitted by all of the observable universe and beyond at the same time.
	2016-03-09: Cosmic Microwave Background Challenge 00:43: In the process, the distance that the average photon could travel went from not very far to greater than the length of the entire observable universe. 02:10: ... those blobs evolve into are now 1,100 times further away, giving us an observable universe that's 93 billion light years ... 03:24: ... need an estimate of the baryonic mass and volume of the observable universe, you'll need the redshift of the CMB, and the Thomson ... 00:43: In the process, the distance that the average photon could travel went from not very far to greater than the length of the entire observable universe. 02:10: ... those blobs evolve into are now 1,100 times further away, giving us an observable universe that's 93 billion light years ... 03:24: ... need an estimate of the baryonic mass and volume of the observable universe, you'll need the redshift of the CMB, and the Thomson Scattering ...
	2016-03-02: What’s Wrong With the Big Bang Theory? 01:00: And at that point, the entire observable universe was around the size of a grain of sand. 04:05: And pack all of the galaxies in the entire observable universe into a space 10 to the power of minus 20th of the width of a proton. 05:40: ... one patch to the next by at most one part in 100,000 across the entire observable ... 07:16: So those edges shouldn't be in each other's observable universes, not then, not now. 11:22: ... would be correct if you add the word "observable" before the word "universe." Everything that we can see to our cosmic ... 11:57: So we restrict ourselves to talking about the size of the observable part of it. 01:00: And at that point, the entire observable universe was around the size of a grain of sand. 04:05: And pack all of the galaxies in the entire observable universe into a space 10 to the power of minus 20th of the width of a proton. 05:40: ... one patch to the next by at most one part in 100,000 across the entire observable universe. ... 11:22: ... "universe." Everything that we can see to our cosmic horizon, so the observable universe, was once compacted into something smaller than a grain of sand, and ... 07:16: So those edges shouldn't be in each other's observable universes, not then, not now.
	2016-02-24: Why the Big Bang Definitely Happened 02:36: ... fact, with raw general relativity, we get that the entire observable universe was once compacted into an infinitesimal point, a singularity ... 07:37: ... early age of 10 to the power minus 32 seconds, when the entire current observable universe was around the size of a grain of sand, give or ... 02:36: ... fact, with raw general relativity, we get that the entire observable universe was once compacted into an infinitesimal point, a singularity at time t ... 07:37: ... early age of 10 to the power minus 32 seconds, when the entire current observable universe was around the size of a grain of sand, give or ...
	2016-02-11: LIGO's First Detection of Gravitational Waves! 03:44: It's expected that an observable merger of two black holes will happen only once every 10,000 years in any given galaxy. 03:56: Advanced LIGO can feel the ripples produced by merging black holes through a volume of space equal to about 0.1% of the observable universe. 03:44: It's expected that an observable merger of two black holes will happen only once every 10,000 years in any given galaxy. 03:56: Advanced LIGO can feel the ripples produced by merging black holes through a volume of space equal to about 0.1% of the observable universe.
	2015-12-16: The Higgs Mechanism Explained 03:40: ... the simplest is to say that while the photon can cross the entire observable universe without bumping into a single thing, the electron is never not ... 09:05: ... merging super massive black holes should have temperatures raised by an observable amount by the gravitational ... 03:40: ... the simplest is to say that while the photon can cross the entire observable universe without bumping into a single thing, the electron is never not bumping ...
	2015-12-09: How to Build a Black Hole 00:21: ... whose boundary curvature effectively removes the interior from our observable ...
	2015-10-28: Is The Alcubierre Warp Drive Possible? 05:08: In fact, it would take significantly more negative energy than there is positive mass/energy in the entire observable universe.
	2015-10-15: 5 REAL Possibilities for Interstellar Travel 02:30: And to do that with any liquid rocket fuel, you'd need a fuel tank larger than the observable universe.
	2015-09-30: What Happens At The Edge Of The Universe? 01:04: In a previous episode, we talked about the size of what we call the observable universe. 03:02: It's a boundary to the observable universe. 04:40: Move to my left, and my observable universe moves with me. 01:04: In a previous episode, we talked about the size of what we call the observable universe. 03:02: It's a boundary to the observable universe. 04:40: Move to my left, and my observable universe moves with me.
	2015-02-25: How Do You Measure the Size of the Universe? 00:52: So we're going to focus on the observable universe. 01:31: And that's the radius of the observable universe. 02:18: ... can expand at a variable rate, complicate how we measure the size of the observable ... 05:13: So that's how we know that the observable universe is about 90 billion light years in diameter. 00:52: So we're going to focus on the observable universe. 01:31: And that's the radius of the observable universe. 02:18: ... can expand at a variable rate, complicate how we measure the size of the observable universe. ... 05:13: So that's how we know that the observable universe is about 90 billion light years in diameter.
	2015-02-18: Is It Irrational to Believe in Aliens? 05:39: ... or that intelligent aliens evolve, none of whom ever spread out in any observable way in the 10-billion-year history of the ...

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